[Merged by Bors] - add ambient lighting hook

crates/bevy_pbr/src/lib.rs

@@ -75,6 +75,8 @@ pub const PBR_PREPASS_SHADER_HANDLE: HandleUntyped =
  HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 9407115064344201137);
 pub const PBR_FUNCTIONS_HANDLE: HandleUntyped =
  HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 16550102964439850292);
+pub const PBR_AMBIENT_HANDLE: HandleUntyped =
+ HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 2441520459096337034);
 pub const SHADOW_SHADER_HANDLE: HandleUntyped =
  HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 1836745567947005696);
 
@@ -132,6 +134,12 @@ impl Plugin for PbrPlugin {
  "render/pbr_functions.wgsl",
  Shader::from_wgsl
  );
+ load_internal_asset!(
+ app,
+ PBR_AMBIENT_HANDLE,
+ "render/pbr_ambient.wgsl",
+ Shader::from_wgsl
+ );
  load_internal_asset!(app, PBR_SHADER_HANDLE, "render/pbr.wgsl", Shader::from_wgsl);
  load_internal_asset!(
  app,

crates/bevy_pbr/src/render/pbr.wgsl

@@ -5,6 +5,7 @@
 #import bevy_pbr::utils
 #import bevy_pbr::clustered_forward
 #import bevy_pbr::lighting
+#import bevy_pbr::pbr_ambient
 #import bevy_pbr::shadows
 #import bevy_pbr::fog
 #import bevy_pbr::pbr_functions
@@ -66,8 +67,6 @@ fn fragment(in: FragmentInput) -> @location(0) vec4<f32> {
  occlusion = textureSample(occlusion_texture, occlusion_sampler, in.uv).r;
  }
 #endif
- pbr_input.occlusion = occlusion;
-
  pbr_input.frag_coord = in.frag_coord;
  pbr_input.world_position = in.world_position;
  pbr_input.world_normal = prepare_world_normal(
@@ -91,6 +90,8 @@ fn fragment(in: FragmentInput) -> @location(0) vec4<f32> {
 #endif
  );
  pbr_input.V = calculate_view(in.world_position, pbr_input.is_orthographic);
+ pbr_input.occlusion = occlusion;
+
  output_color = pbr(pbr_input);
  } else {
  output_color = alpha_discard(material, output_color);

crates/bevy_pbr/src/render/pbr_ambient.wgsl

@@ -0,0 +1,19 @@
+#define_import_path bevy_pbr::pbr_ambient
+
+// A precomputed `NdotV` is provided because it is computed regardless,
+// but `world_normal` and the view vector `V` are provided separately for more advanced uses.
+fn ambient_light(
+ world_position: vec4<f32>,
+ world_normal: vec3<f32>,
+ V: vec3<f32>,
+ NdotV: f32,
+ diffuse_color: vec3<f32>,
+ specular_color: vec3<f32>,
+ perceptual_roughness: f32,
+ occlusion: f32,
+) -> vec3<f32> {
+ let diffuse_ambient = EnvBRDFApprox(diffuse_color, 1.0, NdotV);
+ let specular_ambient = EnvBRDFApprox(specular_color, perceptual_roughness, NdotV);
+
+ return (diffuse_ambient + specular_ambient) * lights.ambient_color.rgb * occlusion;
+}

crates/bevy_pbr/src/render/pbr_functions.wgsl

@@ -233,13 +233,10 @@ fn pbr(
  light_accum = light_accum + light_contrib * shadow;
  }
 
- let diffuse_ambient = EnvBRDFApprox(diffuse_color, 1.0, NdotV);
- let specular_ambient = EnvBRDFApprox(F0, perceptual_roughness, NdotV);
+ let ambient_contrib = ambient_light(in.world_position, in.N, in.V, NdotV, diffuse_color, F0, perceptual_roughness, occlusion);
 
  output_color = vec4<f32>(
- light_accum
- + (diffuse_ambient + specular_ambient) * lights.ambient_color.rgb * occlusion
- + emissive.rgb * output_color.a,
+ light_accum + ambient_contrib + emissive.rgb * output_color.a,
  output_color.a
  );